Local landraces of white clover (Trifolium repens L.) from northwestern Spain by evaluating cyanogenesis, agromorphological characteristics and microsatellites

White clover (Trifolium repens L.), a grass species belonging to the Fabaceae family (Leguminosae or bean family), is an agronomically important pasture legume widely used in moist temperate climates. The Agricultural Research Centre of Mabegondo (CIAM, Xunta de Galicia, Spain) conserves a valuable collection of local white clover landraces originating from Northwestern Spain. The objective of this research was to study 15 local populations and cultivars by evaluating cyanogenesis (the ability to produce hydrogen cyanide after tissue damage), agromorphological traits, and molecular markers. Fourteen simple sequence repeat (SSR) markers were analyzed on a total of 300 DNA samples identifying 300 genotypes. Genetic structure analysis using Structure and Genodive software revealed two reconstructed panmictic populations (RPPs): RPP1 (including 121 genotypes from 7 local populations) and RPP2 (covering 5 local populations and 2 commercial cultivars). A total of 225 alleles were detected, with a higher number of alleles in RPP1 than in RPP2 (189 vs. 164) and of rare alleles (114 vs. 96). Thirteen phenotypic traits were evaluated, including cyanogenic potential. Genotypic structure was related to phenotypic variation, with higher growth in the commercial RPP, albeit with substantial variability inside both RRP. Some of the white clover landraces conserved at CIAM presented low cyanogenic potential, suggesting their potential as locally adapted cultivars for Northwestern Spain.